/**
 * http://www.openjs.com/scripts/events/keyboard_shortcuts/
 * Version : 2.01.A
 * By Binny V A
 * License : BSD
 */
var Shortcut = Class({
	all_shortcuts:{},
	name:'shortcuts',
	
	initialize:function() {

	},
	
	add: function(shortcut_combination,callback,opt) {
		var default_options = {
			'type':'keydown',
			'propagate':false,
			'disable_in_input':false,
			'target':document,
			'keycode':false
		};
		if(!opt) { opt = default_options; }
		else {
			for(var dfo in default_options) {
				if(typeof opt[dfo] == 'undefined') { opt[dfo] = default_options[dfo]; }
			}
		}

		var ele = opt.target;
		if(typeof opt.target == 'string') { ele = document.getElementById(opt.target); }
		var ths = this;
		shortcut_combination = shortcut_combination.toLowerCase();

		//The function to be called at keypress
		var func = function(e) {
			e = e || window.event;
			
			if(opt.disable_in_input) { //Don't enable shortcut keys in Input, Textarea fields
				var element;
				if(e.target) { element=e.target; }
				else if(e.srcElement) { element=e.srcElement; }
				if(element.nodeType==3) { element=element.parentNode; }

				if(element.tagName == 'INPUT' || element.tagName == 'TEXTAREA') { return; }
			}
			
			//Find Which key is pressed
			if  (e.keyCode) { code = e.keyCode; }
			else if (e.which) { code = e.which; }
			var character = String.fromCharCode(code).toLowerCase();
			
			if(code == 188) { character=","; } //If the user presses , when the type is onkeydown
			if(code == 190) { character="."; } //If the user presses , when the type is onkeydown
	
			var keys = shortcut_combination.split("+");
			//Key Pressed - counts the number of valid keypresses - if it is same as the number of keys, the shortcut function is invoked
			var kp = 0;
			
			//Work around for stupid Shift key bug created by using lowercase - as a result the shift+num combination was broken
			var shift_nums = {
				"`":"~",
				"1":"!",
				"2":"@",
				"3":"#",
				"4":"$",
				"5":"%",
				"6":"^",
				"7":"&",
				"8":"*",
				"9":"(",
				"0":")",
				"-":"_",
				"=":"+",
				";":":",
				"'":"\"",
				",":"<",
				".":">",
				"/":"?",
				"\\":"|"
			};
			//Special Keys - and their codes
			var special_keys = {
				'esc':27,
				'escape':27,
				'tab':9,
				'space':32,
				'return':13,
				'enter':13,
				'backspace':8,
				'ctrl':224,
	
				'scrolllock':145,
				'scroll_lock':145,
				'scroll':145,
				'capslock':20,
				'caps_lock':20,
				'caps':20,
				'numlock':144,
				'num_lock':144,
				'num':144,
				
				'pause':19,
				'break':19,
				
				'insert':45,
				'home':36,
				'delete':46,
				'end':35,
				
				'pageup':33,
				'page_up':33,
				'pu':33,
	
				'pagedown':34,
				'page_down':34,
				'pd':34,
	
				'left':37,
				'up':38,
				'right':39,
				'down':40,
	
				'f1':112,
				'f2':113,
				'f3':114,
				'f4':115,
				'f5':116,
				'f6':117,
				'f7':118,
				'f8':119,
				'f9':120,
				'f10':121,
				'f11':122,
				'f12':123
			};
	
			var modifiers = { 
				shift: { wanted:false, pressed:false},
				ctrl : { wanted:false, pressed:false},
				alt  : { wanted:false, pressed:false},
				meta : { wanted:false, pressed:false}	//Meta is Mac specific
			};
			      
			if(e.ctrlKey) {	modifiers.ctrl.pressed = true; }
			if(e.shiftKey) {	modifiers.shift.pressed = true; }
			if(e.altKey) {	modifiers.alt.pressed = true; }
			if(e.metaKey) {   modifiers.meta.pressed = true; }
                        
			for(var i=0; i<keys.length; i++ ) {
				var k=keys[i];
				
				//Modifiers
				if(k == 'ctrl' || k == 'control') {
					kp++;
					modifiers.ctrl.wanted = true;

				} else if(k == 'shift') {
					kp++;
					modifiers.shift.wanted = true;

				} else if(k == 'alt') {
					kp++;
					modifiers.alt.wanted = true;
				} else if(k == 'meta') {
					kp++;
					modifiers.meta.wanted = true;
				} else if(k.length > 1) { //If it is a special key
					if (special_keys[k] == code) { kp++; }
					
				} else if(opt.keycode) {
					if(opt.keycode === code) { kp++; }

				} else { //The special keys did not match
					if(character === k) { kp++; }
					else {
						if(shift_nums[character] && e.shiftKey) { //Stupid Shift key bug created by using lowercase
							character = shift_nums[character]; 
							if(character == k) { kp++; }
						}
					}
				}
			}

			if(kp == keys.length && 
				modifiers.ctrl.pressed == modifiers.ctrl.wanted &&
				modifiers.shift.pressed == modifiers.shift.wanted &&
				modifiers.alt.pressed == modifiers.alt.wanted &&
				modifiers.meta.pressed == modifiers.meta.wanted) {
					callback(e);
	
				if(!opt.propagate) { //Stop the event
					//e.cancelBubble is supported by IE - this will kill the bubbling process.
					e.cancelBubble = true;
					e.returnValue = false;
	
					//e.stopPropagation works in Firefox.
					if (e.stopPropagation) {
						e.stopPropagation();
						e.preventDefault();
					}
					return false;
				}
			}
		};
		
		this.all_shortcuts[shortcut_combination] = {
			'callback':func, 
			'target':ele, 
			'event': opt.type
		};
		
		//Attach the function with the event
		if(ele.addEventListener) { ele.addEventListener(opt.type, func, false); }
		else if(ele.attachEvent) { ele.attachEvent('on'+opt.type, func); }
		else { ele['on'+opt.type] = func; }
		
		return true;
	},

	//Remove the shortcut - just specify the shortcut and I will remove the binding
	detach:function(shortcut_combination, opt) {
		shortcut_combination = shortcut_combination.toLowerCase();
		
		var binding = this.all_shortcuts[shortcut_combination];
		delete(this.all_shortcuts[shortcut_combination]);
		if(!binding)  { return; }
		var type = binding.event;
		var ele = binding.target;
		var callback = binding.callback;

		if(ele.detachEvent) { ele.detachEvent('on'+type, callback); }
		else if(ele.removeEventListener) { ele.removeEventListener(type, callback, false); }
		else { ele['on'+type] = false; }
	},
	
	// removes all shortcuts
	detachAll:function () {
		for(e in this.all_shortcuts) {
			this.detach(e);
		}
	}
});